package day07;

import java.util.Random;

public class VerificationCode {
    public static void main(String[] args) {
        String code = generateVeriCode(4);
        System.out.println("验证码："+code);
    }
    public static String generateVeriCode(int len){
        String code = "";
        char[] chs={'a','b','c','d','e','f','g' ,'h','i',
                'j','k','l','m','n','o','p','q','r','s',
                't','u','v','w','x','y','z','A','B','C',
                'D','E','F','G','H','I','J','K','L','M',
                'N','O','P','Q','R','S','T','U','V','W',
                'X','Y','Z','0','1','2','3','4','5','6',
                '7','8','9'};
        for (int i = 1; i <=len; i++) {
            Random ran=new Random();
            int index=ran.nextInt(chs.length);
            code+=chs[index];
        }
        return code;
    }
}
